Similar Rates of Recurrent SSTIs With Clindamycin and TMP-SMX Therapy

SAN FRANCISCO, CA—Researchers did not observe a difference in recurrent infections when treated with either clindamycin or trimethoprim-sulfamethoxazole (TMP-SMX) in patients with uncomplicated skin and soft tissue infections (uSSTIs), according to results presented at IDWeek 2013.

“Clindamycin and TMP-SMX are commonly used to treat SSTIs, but their efficacy and safety has been understudied,” noted Loren Miller, MD, MPH, from the David Geffen School of Medicine at the University of California-Los Angeles, Torrance, CA. Dr. Miller and his colleagues set out to evaluate the efficacy and safety of these antibiotics in adults and children with uSSTIs.

In this multi-center, randomized, double-blind, controlled clinical trial, patients with uSSTIs from 4 study sites with either cellulitis or abscesses >5cm that had undergone incision and drainage were included. Cellulitis or abscesses were proportionally smaller for younger children.

A total of 524 patients (clindamycin [n=264]; TMP-SMX [n=260]) of which 155 were children (30%), were randomized 1:1 to either the clindamycin or TMP-SMX arm for 10 days. Both investigators and subjects were blinded to treatment and microbiologic results. Test of cure (TOC) was determined 10–14 days after enrollment. The primary outcomes were clinical cure at the TOC visit using intention-to-treat (ITT) and evaluable population models. A one-month follow-up visit (OMFU) was conducted in patients after TOC.

Failure rates of clindamycin and TMP-SMX at test of cure were similar in the ITT (19.7% [14.6–24.8%] vs. 22.3% [16.9–27.7%]; P=0.52). In the evaluable populations, failure rates were also similar (n=467; 10.9% [6.6–15.2%] vs. 11.8% [7.3–16.3%]; P=0.77).

At the OMFU visit, there were no differences in the overall failure rates in the ITT (26.5% [21.0–32.0%] vs. 31.9% [26.1–37.8%]; P=0.18) and evaluable populations (n=459; 16.7% [11.7–21.7%] vs. 21.7% [16.1–27.3%]; P=0.19). Among those subjects who were cured at the TOC visit, there was a trend towards fewer recurrences in the clindamycin group (9.0% [4.9–13.0%] vs. 15.3% [10.1–21.6%]; P=0.051).

Dr. Miller concluded that, “No differences were found in the number of recurrent infections between clindamycin and TMP-SMX treatment groups after one month of treatment completion.”

In general, recurrent infections at OMFU occurred in 25% of the ITT population and 36% of the evaluable population of the overall treatment failures. Among those cured at TOC, 12% had a recurrence or relapse within one month of completing therapy. Researchers also noted a trend towards less frequent failures in patients initially cured with clindamycin vs. those initially cured with TMP-SMX (P=0.051).

“Further research is needed to study the relationship of initial SSTI treatment and rates of recurrent SSTIs,” Dr. Miller added.